What are the diagnostic criteria, typical symptoms, and first‑line treatment options for attention‑deficit/hyperactivity disorder (ADHD) in adults?

ADHD Symptoms in Adults

For adults with ADHD, the diagnosis requires at least 5 symptoms from either the inattention category (e.g., poor attention to detail, difficulty sustaining attention, organizational challenges) or the hyperactivity-impulsivity category (e.g., fidgeting, inner restlessness, excessive talking), with documented onset before age 12, functional impairment in at least two settings, and systematic exclusion of alternative diagnoses such as depression, anxiety, substance use, or trauma. 1, 2

Diagnostic Criteria

Symptom Threshold and Duration

• Adults must exhibit at least 5 symptoms from either the inattention domain OR the hyperactivity-impulsivity domain (or both for combined presentation) that have persisted for at least 6 months. 1, 2, 3
• This is a lower threshold than the 6 symptoms required for children, reflecting developmental changes in symptom expression. 1

Inattention Symptoms to Assess

• Poor attention to detail or careless mistakes in work or other activities. 2
• Difficulty sustaining attention during tasks or conversations. 2
• Appearing preoccupied or not listening when spoken to directly. 2
• Difficulty completing tasks or following through on instructions. 2
• Organizational challenges with time management, meeting deadlines, or keeping materials in order. 2
• Reluctance to engage in tasks requiring sustained mental effort. 2
• Frequently losing items necessary for tasks. 2
• Easy distractibility by extraneous stimuli. 2
• Forgetfulness in daily activities. 2

Hyperactivity-Impulsivity Symptoms to Assess

• Frequent fidgeting with hands or feet, or squirming when seated. 2
• Difficulty remaining seated in situations where it is expected. 2
• Inner restlessness or feeling "on edge." 2
• Being loud or disruptive in leisure activities. 2
• A constant "on-the-go" feeling or acting as if "driven by a motor." 2
• Excessive talking. 2
• Blurting out answers before questions are completed. 2
• Difficulty waiting one's turn. 2
• Interrupting or intruding on others. 2

Mandatory Age-of-Onset Requirement

• At least some ADHD symptoms must have been present before age 12 years—this is non-negotiable and cannot be waived. 1, 2, 4
• When an adult presents without prior diagnosis, establish pre-12-year-old symptom presence through collateral history from parents, review of old report cards, school records, or prior evaluations. 1, 2

Cross-Situational Impairment

• Symptoms and functional impairment must be documented in at least two independent settings (work, home, social relationships, academic environments). 1, 2
• Information must be gathered from multiple sources, including collateral information from family members, partners, or close friends—adults often minimize symptoms when self-reporting. 2

Screening and Assessment Tools

Initial Screening

• Use the Adult ADHD Self-Report Scale (ASRS-V1.1) Part A as the initial screening tool. 1, 2
• A positive screen is defined by endorsing "often" or "very often" on ≥4 of the 6 items, which triggers a comprehensive diagnostic evaluation. 2
• If the screen is positive, complete ASRS Part B to further elucidate symptoms. 1

Comprehensive Assessment

• The Conners Adult ADHD Rating Scales (CAARS) can be used for comprehensive symptom assessment with validated normative data. 2
• Critical caveat: Rating scales do not diagnose ADHD by themselves—a clinical interview is mandatory. 2, 5

Differential Diagnosis: Mandatory Exclusions

Mood and Anxiety Disorders

• Depression and anxiety can mimic inattention and restlessness; optimize treatment of these conditions before confirming an ADHD diagnosis. 2
• Approximately 10% of adults with recurrent depression or anxiety also meet criteria for ADHD—addressing only the mood disorder without evaluating co-occurring ADHD is insufficient. 2
• Bipolar disorder screening is recommended because mood instability is common and requires distinct treatment strategies. 2

Substance Use Disorders

• Substance use, especially marijuana and stimulants, can produce identical symptoms to ADHD. 2
• For ambiguous cases with active substance use, reassess after sustained abstinence before finalizing the ADHD diagnosis. 2
• Some adults may feign symptoms to obtain stimulant medication—document any history of stimulant diversion or misuse. 1, 2

Trauma and PTSD

• Trauma and PTSD can cause hypervigilance, concentration problems, and emotional dysregulation that mimic ADHD. 2
• Treat PTSD before reassessing attention symptoms. 2

Other Psychiatric Conditions

• Psychotic disorders, dissociative disorders, and personality disorders (particularly borderline and antisocial) may present with overlapping symptoms and must be ruled out. 2
• Symptoms must NOT be better explained by oppositional behavior, defiance, hostility, or failure to understand tasks. 1, 2

Physical Conditions

• Sleep disorders, particularly obstructive sleep apnea, should be evaluated as they can produce attention deficits that resemble ADHD symptoms. 2

Comorbidity Screening (Mandatory)

• Systematic screening for comorbid conditions is required because the majority of adults with ADHD meet criteria for another mental disorder. 1
• Screen for anxiety disorders, depression, substance use disorders (particularly alcohol, marijuana, and stimulant misuse), learning disabilities, and sleep disorders. 2
• Approximately 9% of adults with ADHD have comorbid depression. 2
• Continuous monitoring for new comorbidities—particularly emerging depression and substance-use disorders—is essential throughout ADHD treatment. 2

First-Line Treatment

Pharmacotherapy

• Stimulants (amphetamine or methylphenidate formulations) are first-line treatment for adult ADHD, with approximately 60% showing moderate-to-marked improvement. 2, 5, 6
• Titrate doses to achieve maximum benefit with minimum adverse effects. 2, 5
• Clinical guidelines recommend a subset of amphetamine and methylphenidate stimulants as first-line pharmacotherapy, which may be more effective when combined with psychotherapy. 6

Alternative Medications

• For adults unable to take stimulants or with concurrent anxiety/depression, atomoxetine, viloxazine, or bupropion are recommended alternatives. 2, 5, 6
• When active substance use disorder or concern for stimulant misuse is present, non-stimulant agents should be considered as first-line pharmacotherapy. 2

Psychotherapy

• Combination of medication plus psychotherapy is more effective than either alone. 2, 6
• Cognitive behavioral therapy is particularly valuable for improving adaptive functioning. 3

Monitoring and Chronic Disease Management

• Recognize ADHD as a chronic condition requiring ongoing care, following principles of the chronic care model and medical home. 2, 5
• Regular follow-up to assess treatment response, side effects, and functional outcomes is essential. 2, 5
• Consider employing controlled substance agreements and prescription drug monitoring programs to monitor for patient misuse or diversion of stimulants. 2, 6

When to Refer

Refer to a psychiatrist, developmental-behavioral specialist, or neuropsychologist when:

• The clinical picture is complex or atypical. 2
• Active substance-use disorder is present. 2
• Severe mood disorder complicates management. 2
• Treatment-resistant ADHD is encountered. 2
• Suspected personality disorder complicates management. 2